Conventionally, the voltage applied to a word line of a NAND flash memory which is a nonvolatile semiconductor memory varies according to the operation such as reading, programming, or erasing. Furthermore, the voltage applied to the word line differs every word line even in the same operation. In addition, the voltage boosting speed on the word line needs to be controlled suitably.
In the conventional NAND flash memory, therefore, a local pump is provided for every applied voltage in order to select the voltage applied to one word line (see, for example, JP-A-2009-117018 (KOKAI)).